A piezoelectric transformer, which may also be referred to as a piezo transformer, is an electromechanical system which acts as a resonance transformer. The piezoelectric transformer makes it possible to convert a supplied AC voltage into a higher or lower AC voltage. The conversion is able to occur at the resonance frequency of the piezoelectric transformer, which is determined by the mechanical dimensions and the material of the piezoelectric transformer.
One approach for controlling a piezoelectric transformer provides for using the input voltage, the input current, and their phase position as control information. Based on these parameters, control of the piezoelectric transformer and the control of its behavior are able to take place. However, this does not result in the optimal operating point of the piezoelectric transformer being reached. Losses occurring due to non-adjustable control influences affect the performance and efficiency of the piezoelectric transformer. This reactive power is provided by the supplier and converted by the piezoelectric transformer only on the primary side.